Computer assisted total knee arthroplasty: a real navigation to better results?

BACKGROUND AND AIM OF THE WORK: Computer assisted surgery in knee replacement is still in discussion, but majority of papers affirm an increase of the accuracy in alignment. Aim of our study is to evaluate the accuracy of mechanical axis, the posterior tibial slope and the femoral component rotation with navigation, x-ray and CT data. METHODS: We have analysed 145 patients who underwent total knee arthroplasty between January 2012 and December 2014. We have checked each patient at 6, 12 and 24 months of follow-up. During each visit, we did a clinical evaluation checking the ROM and a clinical score (KOOS). At 2 years, we did a CT evaluation and a plain x-ray evaluation. RESULTS: 125 patients have completed the follow-up. Mean follow-up time was 2,6 years. Both ROM and KOOS values increased during follow-up. About the mechanical axis, both x-ray and CT data showed a mean deviation <2° from the target. About posterior tibial slope and femoral component rotation, CT data showed a mean deviation of <3° from the target. Mean difference between navigation and CT data was <1°. CONCLUSIONS: According to literature data, our data confirm that computer assisted surgery in knee replacement have a good accuracy of coronal alignment, rotational alignment and posterior tibial slope.

Acute periprosthetic knee infection: is there still a role for DAIR?

BACKGROUND AND AIM OF THE WORK: Periprosthetic knee infection is a rare complication associated with prosthetic failure; incidence change from 0,4-2% of primary total knee replacement and 5.6% in revisions. Indications for debridment, antibiotics and implant retention (DAIR) are early acute infections or acute delayed infection. Aim of the work is to check if this technique is still a successful in early infections. METHODS: We have analyzed recent literature data on DAIR and all DAIR procedures in our clinic in the last 10 years, the mean time between onset of symptoms and surgery, the mean antibiotic therapy duration and results we have obtained. We evaluate the diagnostic process and different treatments in early knee periprosthetic infections, especially the DAIR approach. RESULTS: If correct indications are followed, DAIR has a success rate in 31-100% of the cases; if it is applied in late chronic infection the success rate is 28-62%. In our experience DAIR has an 80% success rate: in 20 patients treated with DAIR we had 4 failures. CONCLUSIONS: DAIR can be considered a successful treatment, but it depends from individual patient factors, from the microorganisms involved, from the duration of antibiotic therapy and from correct choice in timing and in execution of DAIR by the orthopedic surgeon.

Two-stage revision after total knee arthroplasty.

BACKGROUND AND AIM OF THE WORK: Periprosthetic knee infection is a complication associated with prosthetic failure; incidence change from 0,4-2% of primary total knee replacement and 5,6% in revisions; incidence is increasing over the years. Two-stage revision is the technique used in chronic infection. Aim of the work is to check success rate in our data. Methods. We analyzed retrospectively data of patients who undergone two stage revision surgery between 01/01/2010 to 31/12/2015. We made a clinical and radiological control after 1, 3, 6, 12, 24 months and we evaluate the outcome in December 2016. Results. Between 2010 and 2015 we treated 45 patients with two-stage revision. Mean follow-up was 3,4 years. Success rate is 89,9%. We had failure in 5 patients: everyone had knee surgery before first knee arthroplasty and Charlson Comorbidity Score was greater then 4 in 4 cases. Conclusions. Two stage revision can be considered a successful treatment in chronic periprosthetic knee infection. It has an optimal success rate, but it has some disadvantages as joint stiffness and pain in the interval between stages. This is a technique with two major surgery procedure with associated morbidity, discomfort, cost and prolonged stay in hospital.